Protective apparatus



Filed Sept. 19, 1928 2 Sheets-Shee Inventor Josef Biewmanns, by His Attorney a w w E C N m b D E T w. 5 M f a Oct. 20, 1931. J. BIERMANNS PROTECTIVE APPARATUS Filed Sept. 19, 1928 2 Sheets-Shee 2 Inventor": Joseu Bier'manns,

His Attorney Patented Oct. 20, 1931 UNITED. ,s'rATEs PATENT OFFICE JOSE! B'IERMANRS, OF K AEL SHORST, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY A CORPORATION OF NEW YORK PROTECTIVE APPARATUS Application filed September 19, 1928, Serial No. 806,951; and in Germany October 6, 1927.

- My invention relates to improvements in protective apparatus for electric circuits and more particularly to improvements in protcctive relays and especially those of the type whose time of operation is dependent on the distance between the relay and the fault point. An object of my invention is to provide improved protective apparatus whereby to provide better selectivity throughout the working range of thetime characteristic of relays.

My invention will be better understood from the following description when considered in connection-with'the accompanying drawings and its scope will be pointed out in the appended claims.

Fig. 1 illustrates partly in diagram and partly in perspective an embodiment of my invention; Fig. 2illustrates in plan view a detail of a modification of theembodiment of my invention shown in Fig. 1; Figs. 3 and 4 are'schematic illustrations explanatory of the purpose and principle of my invention; Figs. 5 and 6 illustrate characteristic curves for distance relays and their modification according to my invention; and Fig. 7 illustrates partly in diagram and partly in perspective another embodiment of my invention. V

..' So-called distance relays, that is those whose time of operation is dependent on the distance between the relay and the fault point, are subject to a disadvantage inherent in their construction such that the d'eg sired proportionality between time and dis- 5 tionali'ty is firstobtained at the point (11, at

, a a y and that at the moment of touching the fixed contact 12 the desired line switch or circuit breaker release is efi'ected. In accordance with my invention, it is possible for short distances, that is faults relatively close to the relay to decrease the time of operation of the relay in a desired manner by giving to the contact 12 a certain movement. The simplest arrangement is schematically shown in Fig. 4 in which for the inactive or rest position of the relay, the contact 10 is positioned as shown in Fig. 3 but the contact 12 is movable and in the inactive position of the relay occupies a position 12 that is closer to the contact-10. The moment the member 11 begins to move the contact 12 is also started by any suitable means which may be a motor havinga constant speed which is independent of the speed of the member 11. Contact 12 is kept moving until it has reached the end of its limited movement or extreme position 12 as shown in Fig. i. If the contact 12 requi-resfor example the time 0b to complete its range of moi'cment then if contact 10 completes its movement in a time greater than 0?), nothing will be changed so far as concerns the time of operation since the contacts 10 and 12 cannot engage until the latter'has reached its end position 12. If, however, the contact 10 moves at a greater speed, the contact engagement will take placeybefore the contact 12 has reached its position'12", that is Within a shorter period than with the arrangement according toFig. '3. Consequently, the time of operation will be actually shorter for small distances and to control the circuit of one of the windthe time characteristic instead of being like the curve baa of Fig. 5 will approximate the straight line Oac.

F or the purpose of more fully explaining my invention, I have shown in the embodiment tnereof illustrated in Fig. 1, a distance relay 13 of the type disclosed in my copending application Serial No. 257,731, filed February 28, 1928, and assigned to the same assignee as this invention. As shown, the relay 13 is arranged to control a circuit including conductors 1%, 15, 16 through suitable circuit interrupting means herein shown as a circuit breaker 1'? of the latched-closed type provided with a trip coil 9.

The relay 13 includes a movable member such as a rotatably mounted disk 19 the movement of which is arranged to be controlled by a plurality of electromagnetic motor elements 20, 21 which are inductively related to the disk. he motor element 20 is responsive to a current of the circuit 14, 15, 16 and includes a magnetic core 22 provided with windings and a cooperating magnetic member 26. The windings 23, 21, 25 are connected to'be energized in accord ance with the current in a conductor 16 of the circuit through means such as a current transformer 2?, suitable phase displacing means shown as a resistor 18 being employed. The motor element 20 may be constructed as set forth in German Patent 316,599 so as to provide a torque which is substantially proportional to the first power of the current by having the magnetic circuit of one of the windings such as 24 arranged to saturate at some predetermined current. The motor element 20 is an operating element and exerts a torque which tends to turn the disk 19 in the direction indicated by the arrow 28.

The motor element 21 may be similar in construction to the motor element 20, that is including a magnetic member 22 whose branches are provided with windings 23,

241, 25 and a cooperating magnetic member 26. The windings 23, 24c, 25' are connected to be energized in accordance with a voltage of the circuit 14, 15, 16 such as the voltage between the phase conductors and 16 through suitable means shown as a potential transformer 29. Suitable phase displacing means such as a resistor 18 may be placed in circuit with the windings 23, 24. 25'. The motor element 21 is a restraining element and exerts a direct torque which opposes the torque of the current energized. motor element and tends to turn the disk 19 in the direction opposite to that indicated by the arrow 28. Motion in this opposite direction is limited by suitable means such as the extension 30 on the shaft which supports tie disk 19. this extension coming to rest against a stop 31.

The movement of the disk 19 is arranged ings 23, of the voltage element 21 so as to change the action thereof from a direct torque to a damping torque, when the current or operating element 20 in response to current of a predetermined value exerts a torque which is sufiicient to overcome or predominate the direct torque of the voltage or restraining element 21. For this purpose, the circuit of the windings 23, 25, includes contacts 32 which are arranged to be actuated by the extension so they are normally closed and arranged to be opened on movement of the disk 19 in the direction indicated by the arrow 28. The disk 19 is arranged to actuate a movable member which may be in the form of a contact 10.

Instead of having the movable contact 10 cooperate with a fixed contact 12 after the manner pointed out in connection with the description of Fig. 3, I arrange in accord ance with my present invention to provide a cooperating movable member such as a contact 12 which is arranged for a limited movement. Further in accordance with my in vention, I provide means which may be operative substantially simultaneously with the actuation of the movable contact 10 for moving the cooperating contact 12 away from the contact 10 after the manner set forth in connection with the explanation of Fig. l.

The means for actuating the cooperating contact 12' may be of any suitable type according to the particular time characteristirdesired but, as shown in Fig. 1, the actuating means 33 is of the induction disk type and includes a disk 31 and a motor element 35. The motor element may be of the same type as the motor element 20 and as shown is arranged to be energized by the current in the conductor 16 on the initial movementof the disk 19 or the contact 10.

Where it is desired to obtain substantially constant velocity for the contact 12 the windings of the motor element 35 may be energized through a transformer 36 which is arranged to saturate at for example normal line current As shown, the motor element comprises a plurality of windings 36, 37, 33 of which 36 and 38 are normally deenergized but are arranged to have their circuit con trolled upon movement of the disk 19 of the distance relay 13 through contacts 39 controlled by a member 40 movable with the disk so as to maintain the contacts 39 open in the normal or inactive position of the relay. So long as the motor element 35 has its windings 36, 38 deenergized, it exerts no torque but upon closing of the contacts 39 in response to the operation of the distance rclav 13, the motor element 35 exerts a torque tending to turn the disk 34 in the direction indicated by the arrow 41. The movement of the disk 34 and, therefore, the contact 12 is limited by stops 42, 43 against the former of iii) which the contact 12 is normally biased the inactive or stationary position by a light spring .44. The movement'of the disk 34 may be dampedby a suitable magnet'45 for'rctarding the n'iovement of the disk.

Under normal conditions the parts will be positionedasshown 1. Uponthe occurrence of a fault'on thercircuit 14, 15, 16

the disk 19 will be actuated thereby changing the operation of the-motor element :21 from: a directtorque device to a damping torquede vice. Alsothe-actuatingmeans33 ofthe cooperating contact 12 will beenergized upon the closing of the contacts 39 therehystarting the movement of the disk 34 so that the contact 12'tends to move awayfrom the stop .42 toward the stop 43. If the fault is at some distance fromthe relay, the contact 12' will have time to be actuated to its final position i against the stop 43 before'it 'is'engaged by the contact 10 since the time-'of movement of the latter will be relatively great. 51f, however, the fault is comparatively-close to the relay, the time of movement of the contact 1 1 will be short-and it'will overtake contact 12 at someposition prior to-its extreme position against stop 43 and,consequently, the contact will not have-tomove'as far'as it would if the contact 12 were fixed in its extreme position against stop 43'all thetime. Therefore, the time of operation of the relay is de creased for nearby faults after the manner shown by the'curvesin Fig. 5.

"My invention is not limited to an arrangement wherein the speed of the cooperating contact 12' has'to be constant bnt'can-bemade dependent on electrical quantities-of the circuit. Also it is not necessary that the movement of the contact 12' occur simultaneously with themovement of the disk 19. By controlling the movement of the cooperating contact '12 as well as its direction of movement relatively tot-he contact 10, any desired relation between time and distance and the initial portion of the time characteristic can be obtained. For example, the cooperating contact 112" may first be moved away from and then toward the movable contact 10 in order to compensate a time characteristic of the form indicated by the curve b'yac' shown in Fig. 6.

A detail of a partial modification of the embodiment of my invention shown in Fig. 1

whereby the compensation illustrated in Fig.

"6 can be obtained is shown in Fig.2. In this figure the disk 34 of the actuating means 33 of Fig.1- instead of having the cooperating contact 12 rigidly secured thereto, is arranged to control a contact 120 which is pivotally mounted at 44 and is provided with a slot arranged to tie-engaged by a pin 45 mounted on the disk. The movement of the disk 34 is between two stops 42 and '43. In the normal or initial position of the disk against the stop 42', the contact lw occupies ithe broken l'in'e o'a ithe'ipositionshown in full lines but upon movement or the disk in the direction indicated'hy the-arrow 4 1 the pin-45 moves to the position :45 so that the contact 1 ino've away from the movable contact 10 to the position 120 indicated by 1 a broken line. -As the disk '34 moves so'that the p'in45 goes from the position to the position 45 and the disk comes up against its other stop-43 the movement of thecontact 120 is reversed or toward the contact 10 "to a position 120 shown by a broken 'line.

In this modification of my invention, of

course, as the contact is moved lZ-lH'OU-gl'I the range 45 45 ltheltende'ncy is to shorten the time ofoperationfor nearby faults afterthe manner heretofore eXplained,-' and the initial P rtion ba of' the characteristic curve bac such asbac concave up as shown can be modified into-the curve 0a0'which is concave down. -It wi1l,of course, be obvious to thoseskilled intheart thatif, instead ofhatvthen'toward the contact 10, it is first moved towardand'then away from the contact 10,a

characteristic curve which is concave down can be modified toone which is'con'caveup.

In Fig. I have 's'hown amodifica'tion of my invention as applied to a distance relay 13 ofthe t ype disclosed in my United States Letters Patent 1,530,290, dated March 17,

1925, and assigned to the same assignee as this invention. This distance 'relayisof the type'in' which an additional impulse or force which may beobtained as shown by an overcurrent relay 46 and which, apart from the torque acting during the entire period of operation of'the relay, acts on the main movable part or disk 47 quickly to accelerate it in a direction indicatedfiby the arrow 48. The disk47 is arranged'to be actuated by a motor element 49 including amag'netic core 50 on which are mounted a winding 51 connected tobe energized "in accordance with the current in a conductor 16 of the circuit 14.

15, 16 and windings '52, 53 connected to be energized in accordance with the voltage be- "tween the conductors 15 and 16. The motor element '49 further includes a cooperating magnetic member 54. The movement of the disk '47 is arranged to actuate a con-tact with a discriminating time act-ion dependent on the impedance-and a component o f 't he impedance of an electric circuit between the relay location and a fault as'pointed out in my Patent 1,530,290. The concact'st is, in

ill)

the normal or inactive position of'the relay, at rest against a stop 56 against which it may be biased by suitable means such as a spring 57. The overcurrent relay 46 is arranged. to close contacts 58 in the circuit of the voltage windings 52 and 53 and may also be arranged to control contacts 59 in the circuit of the trip coil 9 011 the occurrence of a fault.

In accordance with my present invention instead of having the contact which cooperates with the contact fixed, I provide a movable contact 12 which is arranged for a limited movement between two stops 42, 1 .3 and which is arranged to be moved away from the contact 55 on the occurrence of an abnormal circuit condition. In this case the actuation of the contact 12 is brought about through the operation of the overcurrent relay 4:6 by suitable means indicated as a rack 60 and a pinion 61. In order that the contact- 12 may have throughout its movement the same velocity which the contact 55 would have it it were'moved solely under the influence of the overcurrent relay, suitable energy storing means such as a spring 62 is interposed between the movable part of the overcurrent relay 4G and the rack 60. This further tends to provide a uniform move ment or definite timing operation of the contact 12 and asuitable load may be imposed on the movement by means such as a disk 63 arranged for movement with the contact 12 and under the effect of a drag magnet 64.

\Vhile I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown but seek to cover in the appended claims all those modifications that fall with o in the true spirit and scope of my invention.

\Vhat I claim as new and desire to secure by Letters Patent of the United States is 1. In combination with an electric circuit and circuit interrupting means therefor, a relay for controlling said interrupting means including a movable member, a cooperating member arranged for a limited movement, means connected to be energized in accordance with current and a voltage of the circuit for actuating said movable member and means operative substantially simultaneously with the actuation of said movable member for moving the cooperating member away from the movable member. Q

In combination with an electric circuit and circuit interrupting means including a movable contact and a cooperating contact arranged for a limited movement, electromagnetic means connected to be energized in accordance with a current and a voltage of the circuit for actuating said movable contact and means operative substantially simultaneously with the actuation of said movable contact formoving the cooperating contact away from the movable contact.

3. A time element relay including a movable member, a normally stationary cooperating member, electromagnetic means for actuating said movable member and means for causing a portion of the time element characteristic of the relay to differ from its condition with said cooperating member stationary including means operative substantially simultaneously with the actuation of said movable member for moving said cooperating member within predetermined limits.

4. A relay including a movable member, a. cooperating member arranged for a limited movement, electromagnetic means for actuating said movable member and means operative substantially simultaneously with the actuation of said movable member for first moving the cooperating member away from and then toward the movable member.

5. A protective relay including a movable contact, a cooperating contact arranged for a limited movement, current operating and voltage restraining means for controlling the actuation of said movable contact and means responsive to the initial movementof said movable contact for moving the cooperating contact away from the movable contact at a substantially constant velocity.

6. A protective relay including a movable contact, acooperating contact arranged for a limited movement, current operating and voltage restraining means for controlling the actuation of said movable contact and means responsive to the initial movement of the movable contact for first moving the cooperating contact away from and then toward the movable member.

7. In combination with an electric circuit and a distance relay having a movable member with a. time characteristic dependent on the voltage and the current of the circuit, means for varying a portion of the time characteristic of the relay including another member arranged to cooperate with said movable member and having a limited movement, and means arranged to be energized on the occurrence of a fault on the circuit for moving said other member away from the movable member.

8. In combination with an electric circuit, a distance relay having a movable contact, means for actuating said movable contact in a time dependent on the distance between the relay and the location of a fault on the circuit, means for decreasing the time of operation of the relay for faults relatively close to the relay including another contact arranged to cooperate with said movable contact and having a limited movement, and electromagnetic means arranged to be energized on the occurrence of a fault on the circuit for moving said other contact away from the movable contact at a substantially constant velocity.

9. A time element relay including a movable member, a cooperating member arranged to assume a predetermined position, electromagnetic means for actuating said movable member and means for causing a portion of the time element characteristic of the relay to differ from its condition with said cooperating member in said position including means operative substantially simultaneously with the actuation of said movable member for moving said cooperating member from said position.

In witness whereof, I have hereunto set my hand this 4th day of September, 1928.

JOSEF BIERMANNS. 

